When you are opening models from the working directory File Open dialog shows the directory content, just like you can see it in windows explorer. There are options to show the files details like size and date but everything is based on extracting the file properties.
When you are trying to load a model from a library it is possible to define a index or menu file that provides more than just the file properties. This is the case with Manikin Library. If you open <Creo loadpoint>\CommonFiles\manikin_lite directory in windows explorer you will find a file named "index.lst". This is the file that has all the details for the additional column in the Open dialog.
This style of files seems to be specific only to manikin libraries. Other libraries are using "menu" files. The syntax for this type of files is described in Article CS110191
